Re: [PATCH tip/core/rcu 2/9] x86/kvm/pmu: Replace rcu_swap_protected() with rcu_replace()

[Paolo Bonzini <pbonzini@redhat.com>]

On 03/10/19 03:43, paulmck@kernel.org wrote:
> From: "Paul E. McKenney" <paulmck@kernel.org>
> 
> This commit replaces the use of rcu_swap_protected() with the more
> intuitively appealing rcu_replace() as a step towards removing
> rcu_swap_protected().
> 
> Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/
> Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: <x86@kernel.org>
> Cc: <kvm@vger.kernel.org>
> ---
>  arch/x86/kvm/pmu.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 46875bb..4c37266 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -416,8 +416,8 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
>  	*filter = tmp;
>  
>  	mutex_lock(&kvm->lock);
> -	rcu_swap_protected(kvm->arch.pmu_event_filter, filter,
> -			   mutex_is_locked(&kvm->lock));
> +	filter = rcu_replace(kvm->arch.pmu_event_filter, filter,
> +			     mutex_is_locked(&kvm->lock));
>  	mutex_unlock(&kvm->lock);
>  
>  	synchronize_srcu_expedited(&kvm->srcu);
> 

Should go without saying, but

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Paolo